Bolt anchor



W 1929- J. J. RAWLINGS I 1,708,896

BOLT ANCHOR Filed June 6, 1925 ATTOR/V Patented Apr. 9, 1929.

UNITED .sTATEs PATENT OFFICE.

J OHN JOSEPH RAWLINGS, OF LONDON, ENGLAND, ASSIGNOR 0F ONE- HALF TO THE RAWLPLUG COMPANY LIMITED, OF LONDON, ENGLAND.

BOLT ANCHOR.

Application filed June 6, 1925, Serial No. 35,413, and in Great Britain June 18, 1924.

, This invention relates to an improved bolt anchor or device for securing bolts, hooks, railing posts and the like in prepared holes in stone, concrete, brick and like floors, wallsor similar structures.

Heretofore bolts have been anchored in prepared holes in building stones by pouring molten lead into the hole around the bolt after the bolt has been placed in the hole and tampering by or caulking the lead after it has cooled in order to expand it into close contact with the bolt and the walls of the hole.

According to this invention a bolt anchor is provided in the nature of a washer or dis tance piece adapted to be slid on to the shank of a bolt after the head of the bolt has been inserted in a hole in .which the bolt is to be secured, and comprising a ring shaped substantially conical or frusto-conical hollow body of metal separable into segmental pieces made preferably of hard metal, which, when inserted in a hole made to receive a bolt head, respectively occupy inclined positions around the shank of the bolt, with one end of the piece or segment resting in the corner between the shank and the head of the bolt, and with the other end of the piece or segment near to or resting against the wall of the hole. In order that these pieces or segments can conveniently be inserted in the required position within a hole, means are provided to hold the segments together in a ring-shaped or conical formation, the means for thus holding the segments together being of such a character that the connection between adjacent segments can be readily broken to allow the segments to be spread apart within the hole. Thus the segments may be held to gether by thin webs, the whole forming an integral structure, or the segments may be held together by a band of wire or the like, or thes'egments may be set in a soft metal carrier.

In the accompanying drawing:

gigure 1 is a central longitudinal section, an

Figure 2 an end view of a bolt anchor made in accordance with this invention.

Figures 3 and 4 are views similar to Figures 1 and 2 respectively, illustrating an alternative construction of bolt anchor.

Figures 5, 6, 7 and 8 illustrate further alternative constructions of bolt anchor.

Figure 9 is a partial longitudinal sectional view illustrating a bolt anchor in a position before the segments are rendered operative.

Figure 9 is a partial longitudinal sectional view showing the segments arranged in an operative position.

gigure lOis a central longitudinal section, an V Figure 11 is an end view of a bolt anchor gomprising segmental pieces with roughened aces.

Figures 12 to 15 illustrate further modifications or constructional forms of bolt anchor.

Figure 16 is a partial longitudinal section illustrating a bolt anchor in position before the segments are moved into an operative position.

Figure 16 is a partial longitudinal sectional view showing the segments arranged in an operative position. 1

As shown in Figures 1 and 2-, the bolt anchor consists of a hollow substantially conical or frusto-conical body or ring A having a number of radial or axial slots D formed in the part of larger diameter which divide the body or ring into a number of segments held together by thin or slight Webs E which can be readily broken by pressure applied to spread apart the free ends of the several seg ments.

As shown in Figures 3 and 4, a, a are a number of separate segmental pieces of hard steel or chilled cast iron set spaced'apart in the frusto-conical end surface of a hollow tubular part 7) of lead, which may be cast on to the segmental pieces a, the said pieces a preferably having their lateral edges slightly backed off or tapered so that they are firmly held in the lead until the anchor is put to use. The exterior faces of the segmental pieces extend from the smaller end of the frusto-conical surface to the larger end thereof and the smaller end of the frusto-conical surface is slightly larger in diameter than the bolt shank on to which it is to be threaded whilst the diameter of the larger end of the conical surface is approximately equal to that of the bolt head. Figures 5 and 6 show a hollow lead cylinder Z) fitted at one end with a frusto-conical part c of hard inflexible metal having slots 03 therein into which the metal composing the cylinder 6 can flow to hold the parts together. These slots also pro vide planes of Weakness at which the frustoof soft metal; and in conical part a can be broken into separate segmental pieces substantially like each of the pieces a in Figure 1, only a thin rim or web 6 being left around the ends of the slots so that there is only a small resistance to fracture.

In the alternative arrangement illustrated in Figures 7 and 8, a ring or washer f of a substantial thickness is provided from which the segmental pieces 9 project, each piece 9 being attached to the washer f by a thin web g only.

Bolt anchors of the forms illustrated are put to use substantially in the manner hereinafter described with reference to Figure 9 in which 71. represents a block in which a bolt 2' is to be anchored. A bolt 71 is thrust into a hole j in the block until the head I: of the bolt abuts against the bottom of the hole which is made of-a sufficiently large diameter to allow insertion of the bolt head as required. A bolt anchor is then threaded on the stem of the bolt and pushed into the hole until the hard metal end of the anchor abuts against the bolt head, as shown in the upper part of Figure 9. The soft metal I) is then driven deeper into the hole by means of a tamping tool, punch or other suitable means and expanded therein as shown in the lower part of Figure 9. In effecting this the soft metal is compressed against the segmental pieces of hard metal which are thus spread outwardly and become wedged between the bolt head and the wall of the hole, the webs a between the segmental pieces, in the case of the construction shown in Figure 5, being broken. When the bolt anchor is of the form shown in Figure 7, after the segmental pieces have been broken off therefrom the washer provides a surface against which the fractured end of the segmental pieces rest.

- The ends of the hard metal segmental pieces which are pressed against the wall of the hole may be formed with more or less sharpened edges and the ends resting against the bolt are preferably blunt or rounded. The segmental pieces are advantageously made thicker at their central portions and taper towards the sharp ends and the rounded ends, as shown in the drawing.

As shown in Figures 10 and 11, the body or ring A, or each segmental piece into which it can be divided, is formed with a rounded edge at e and a curved or oblique surface m which is grooved, stepped or roughened. In the form of the bolt anchor now described, the segments are thicker towards the ends thereof intended to bear against the wall of a hole in which they are inserted.

In the arrangement shown in Figures 12 and 13 a number of separate segmental pieces a of hard metal similar in shape to those shown in Figures 10 and 11 are embedded in the conical end surface of a tubular plug .7) Figures 14 and 15 a ring A similar to that shown in Fi ure 10, is shown in combination with a tuliular soft metal plug 6.

' The bolt anchor segments with roughened oblique or eccentric ends, when spread apart in a hole as hereinabove described with reference to Figure 9, grips the wall against which their roughened ends engage, and any force tending to draw the bolt i out of the hole tends to cause the oblique or eccentric ends to roll on the wallof the hole as will be obvious from an examination of Figure 16. This rolling movement increases the gripping or wedging effort exerted by the segments against the wall of the hole.

I claim:

1. A bolt anchor for insertion in a hole in which a bolt is to be secured, comprising a body of soft metal, and segmental pieces of hard metal embedded in the body of soft metal with their exterior surfaces arranged in frusto-conical formation, the said segmental pieces of hard metal being adapted to be spread outwardly by expansion of the diameter of the soft metal body when the anchor is in position in the hole in order to contact with the wall of the hole to form struts.

2. A bolt anchor for insertion in a hole in which a bolt is to be secured, comprising a body of soft metal, segmental pieces of hard metal embedded in the body of soft metal with their exterior surfaces arranged in frusto-conical formation, and websconnecting the segmental pieces together, the said segmental pieces of hard metal being adapted to be spread outwardly, by expansion of the diameter of the soft metal body when the anchor is in position in the hole in order to contact with the wall of the hole to form struts.

3. A bolt anchor for insertion in a hole in which a bolt is to be secured, comprising a body of soft metal having a bore therethrough of larger diameter than the diameter of the bolt, and whose outer diameter is less than the diameter of the hole in which it is to be inserted, scglnental pieces of hard metal embedded in the body of soft metal with their exterior surfaces arranged in frusto-conical formation, and webs connecting the segmental pieces together, the said segmental pieces of hard metal being adapted to be spread outwardly by expansion of the diameter of the soft metal body when the anchor is in position'in the hole in order to,

contact with the wall of the hole to form struts.

4. A bolt anchor for insertion in a hole in v which a. bolt is to be secured, comprising a the soft metal body at one end thereof, with their exterior surfaces arranged in frustoconical formation, and webs connecting the segmental pieces together.

5. A bolt anchor for insertion in a hole in which a bolt is to be secured, comprising a V tubular body of'soft metal having an interior diameter larger than the diameter of the bolt, and an exteriordiameter less than the diameter of the hole in which it is to be inserted, segmental pieces of hard metal embedded in the soft metal bod at one end thereof with their exterior sur aces arranged in frustoconical formation and webs connecting the segmental pieces together, the larger end of the cone of hard metal being co-axial with and adjoining the exterior surface of the tubular soft metal body, the said segmental pieces of hard metal being'adapted to be spread outwardly by expansion of the diameter of the soft metal body when the anchor is in position in the hole in order to contact with the wall of the hole to form struts.

6. A bolt anchor comprising a soft metal tubular plug having a frustoconical end, and" a plurality of segmental pieces of hard metal embedded in the said frustoconical end with their exterior surfaces in frustoconical formation to form a unitary structure.

7 A bolt anchor comprising a soft metal tubular plug having a frustoconical end, a

' plurality of segmental pieces of hard metal embedded in the said frustoconical end with their exterior surfaces in frustoconical formation to form a unitary structure, each of said segmental pieces having a rounded surface at one end and a toothed surface at the other end.

8. A bolt anchor comprising'a soft metal tubular plug having a frustoconical end, a plurality of segmental connected together by; frangible webs, this hard metal structure eing embedded in the said frustoconical end with the exterior surfaces of said segmental pieces in frustoconical formation to form a unitary structure.

9. A bolt anchor comprising a soft metal tubular plug having a cylindrical body portion and a frustoconical end, and a number of segmental pieces of harder metal than said body portion embedded in frustoconical formation in the said frustoconical end of the jsoft metal plug to form a unitary structure.

10. A bolt anchor comprising a soft metal tubular plug having a. cylindrical body portion and a frustoconical end,-and a number of segmental pieces of harder metal than said body portion embedded in the said frustoconical end of the soft metal plug to form a unitary structure, said body portion having webs of soft metal extending between the segmental pieces of harder metal.

JOHN JOSEPH RAWL-INGS.

pieces of hard metal 

